calculus
Pluralcalculi (some meanings), calculuses (some meanings)
- 1The branch of mathematics made up of differential and integral calculus, treated as a single subject.
Engineering students have to pass calculus before they can start most of their core courses.
Newton and Leibniz each developed the calculus on their own in the late 1600s.
UsageUsually no article: take calculus, pass calculus. The calculus appears when it is treated as one discovery, as with Newton.
Note
The subject's name is short for infinitesimal calculus, as it was originally called, and the short form covers both its differential and integral branches. Older writing often calls it the calculus, treating it as one body of method.
- 2A method for making decisions, especially one suited to a particular specialized field.
The senator's political calculus shifted once the polls showed voters turning against the bill.
Doctors face a grim moral calculus when there are more patients than ventilators.
UsageUsually with a describing word: political calculus, moral calculus. New facts can change the calculus.
Similarcalculation, reckoning
- 3Any formal system for working with symbolic expressions by applying a fixed set of rules.
In the predicate calculus, a proof is a sequence of formulas, each following from earlier ones by a stated rule.
Process calculi give computer scientists a precise way to describe programs that run at the same time.
Note
Logicians and computer scientists use the word for a whole family of systems, each named by a qualifier: the predicate calculus, the lambda calculus, process calculi. What they share is that every step is mechanical, a rewriting of symbols by stated rules with no appeal to what the symbols mean. In this technical sense the plural is calculi.
Checked 31 Oct 2026 · 1 fact
- Steps within a formal calculus apply mechanical rules to symbolic forms independently of their meanings. ojs.ppke.hu
- 4Mineral deposits of calcium phosphate salts that form on the surfaces of the teeth.
The hygienist removed a heavy buildup of calculus along the gum line.
Calculus that forms below the gums can irritate the tissue and lead to gum disease.
UsageMost patients call it tartar; dentists speak of a buildup of calculus.
Similartartar
Note
It is plaque that has hardened by taking up minerals, so brushing cannot shift it and it has to be scraped away; tartar is the name most patients know. Calculus above the gum line is told apart from the kind that forms beneath it.
Checked 2 Nov 2026 · 5 facts
- Dental calculus is plaque hardened by mineral deposition. en.wikipedia.org
- Brushing cannot remove established dental calculus. nidcr.nih.gov
- Dental calculus is removed by scaling or scraping with dental instruments. cdn.teethrelief.org.uk
- Tartar is another name for dental calculus. nidcr.nih.gov
- Dental calculus occurs above and below the gum line. my.clevelandclinic.org
- 5A hard, stony mass that builds up inside one of the body's organs.
A single large calculus was blocking the salivary duct and had to be removed surgically.
The ultrasound revealed several calculi lodged in the patient's gallbladder.
UsageThe plural is calculi. In everyday speech these are stones: kidney stones, gallstones.
Similarstone
Note
Here the Latin pebble behind the old sense of reckoning comes back almost literally, as a small stone in the body. Medical writing keeps the Latin plural, calculi, and names a stone by where it forms: renal calculi in the kidney, biliary calculi in the gallbladder, crop calculi in a bird.
Checked 2 Nov 2026 · 4 facts
- Calculus comes from Latin calculus, meaning a pebble or stone used in reckoning. en.wiktionary.org
- Renal calculi are kidney stones. en.wikipedia.org
- Biliary calculi include stones formed in the gallbladder. ncbi.nlm.nih.gov
- Calculi can form in a bird's crop. harrisonsbirdfoods.com
Less common meaning
- 6The act or process of working out an amount or result with numbers.
Similarcalculation, computation, reckoning
Note
The general sense of reckoning sits closest to the Latin: a calculus was a small pebble, from calx, "limestone," used as a counter on an abacus.
Checked 2 Nov 2026 · 3 facts
- Latin calculus meant a small pebble. mathshistory.st-andrews.ac.uk
- Calculus derives from calx, meaning limestone. mathshistory.st-andrews.ac.uk
- Pebbles were used as counters on an abacus. en.wikipedia.org
Practice
Can you tell the meanings of calculus apart? Answer 3 quick questions from this page, or write your own sentence and AI will check it.
Origin
Latin calculus, a diminutive of calx ("limestone"), meant a pebble used as a counter on an abacus, and English borrowed it. The math meaning was taken from the term differential calculus.